Shepherd, 70, left the Magpies in 2007 and is estimated to be worth around £75m.
His return to football has come as he is one of the men reportedly helping a bid for the Glasgow side being fronted by Charles Green.
Shepherd is now part of the Triple S Sports and Entertainment Group along with his football agent son, Kenneth, and Paul Stretford, the agent who represents Manchester United’s Wayne Rooney.
An unconditional offer from former Sheffield United chief executive Green has been accepted by administrators.
Shepherd has connections with the Glasgow club, and brough chief executive Freddy Fletcher (also pictured) to St James' Park from Ibrox in 1992.
Fletcher, along with then-chairman John Hall, re-shaped the club and the stadium and turned it into what we know now.
Source: FOOTYMAD
